JPH03195343A - Magnetizer for step motor - Google Patents

Abstract

PURPOSE:To facilitate manufacture of a high torque, high output motor by integrally magnetizing a permanent rod magnet burried in the tooth groove of rotor core and a permanent disc magnet for main flux field arranged between the rotor cores. CONSTITUTION:Yokes 23a, 23b are magnetically isolated through a nonmagnetic ring 24 to form independent magnetic circuits with a magnetizing yoke 23 and a rotor core 7 thus forming flux loops 25a, 25b. Since the flux loops 25a, 25b have same rotational direction, radial magnetic flux penetrates reversely through permanent rod magnets 10a, 10b placed in the rotor teeth 8a, 8b in respective blocks thus magnetizing permanent magnets 10a, 10b reversely. Since the magnetizing coil 21 for a permanent disc magnet 9 arranged on the nonmagnetic ring 24 has air core, the magnetic circuit is opened thus forming a magnetizing field penetrating through a rotor shaft 11 in the axial direction. By such arrangement, both permanent magnets can be magnetized integrally upon finish of rotor machining and assembly under non-magnetized state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a magnetizer for a stepping motor.

(Prior Art) There is a demand for the development of a small, lightweight motor with high output density (motor torque/motor weight) as an actuator for the drive mechanism of precision control equipment for OA and FA.

A stepping motor having an inductor is generally used as a motor that generates high torque.

Since a stepping motor has a large number of teeth (inductors) on the air gap surface, the air gap magnetic flux density changes as the magnetic resistance changes depending on the rotor position. This changes the magnetic energy, producing 1-lux.

However, if the air gap length is narrowed or the magnetic loading/electrical loading is increased, the torque will not increase much due to magnetic saturation of the core teeth and leakage of magnetic flux to the tooth sides, resulting in a disadvantage that the motor will become larger.

Therefore, the following stepping motor has been developed to improve this drawback.

4, 5, and 6 show a high-torque, high-mountain chipping motor that is the object of the present invention. A multi-phase winding 3 is wound around each stator pole tooth 2, and a plurality of stator teeth 4 are provided on the inner circumferential surface of each stator pole tooth 2. A stator 6 to which a rod-shaped permanent magnet 5 magnetized in the radial direction is fixed.
A plurality of rotor teeth 8 are provided on the outer circumferential surface of the rotor core 7 facing the stator small teeth 4, and the rotor teeth 8 are divided into two in the axial direction, and the rotor teeth 8 are arranged at a 1/2-tooth pitch with each other. The rod-shaped permanent magnet 5 of the stator is composed of a rotor 11 having a disk-shaped permanent magnet 9 magnetized to
The stepping motor is designed to have high torque and high output by setting the polarity of the rod-shaped permanent magnet 10 of the rotor in a direction that cancels out the main magnetic flux generated by the disc-shaped permanent magnet 9. In addition, the code|symbol 12 shows the rotation axis of the rotor 11.

By the way, when a conventional air-core coil magnetizer 16 equipped with an axial magnetizing coil 15 shown in FIG. 7 is used in the manufacturing process of the motor described in 2. Become.

That is, as shown in FIG. 8, after two blocks of rotor core 7 and unmagnetized disk-shaped permanent magnets 9 are attached to the rotating shaft 12, the disk-shaped permanent magnets 9 are attached by the air-core coil magnetizer 16 shown in FIG. is magnetized in the axial direction.

Next, rod-shaped permanent magnet 5. A single JO is magnetized in the thickness direction (direction perpendicular to the motor axis direction) by an air-core coil magnetizer 16. The magnetized bar-shaped permanent magnets 5, 10 are placed in the grooves of the rotor teeth 8 as shown in FIG.
Insert the books one by one while pushing in the axial direction. In the entire rotor, twice the number of rod-shaped permanent magnets 10 as the number of rotor teeth are inserted.

(Problem to be Solved by the Invention) However, as shown in FIGS. 4, 5, and 6, the number of rotor teeth for high-torque types ranges from several tens to several hundreds. Bar-shaped permanent magnet 1 embedded in the groove
The width and thickness of 0 is quite thin at 0.5 to 2 m, and
Since the rod-shaped permanent magnet 10 is magnetized, it hits the rotor teeth 8 due to its own magnetic attraction and is easily damaged by the impact. As described above, the bar-shaped permanent magnets 10 have a poor yield in magnetization and attachment, and the number of bar-shaped permanent magnets 10 in the entire rotor is twice as many as the rotor teeth 8, making mass production difficult.

In addition, the rotor 11 is manufactured by magnetizing the disk-shaped permanent magnet 9.
After magnetization, the magnetized and magnetized bar-shaped permanent magnet 10 is inserted and fixed into the groove of the rotor teeth 8. However, the polarity of the disc-shaped permanent magnet 9 and the bar-shaped permanent magnet 10 are opposite, and when the bar-shaped permanent magnet 10 is inserted into the groove of the rotor teeth 8, it receives a repulsive force, resulting in poor workability and the magnet may be damaged. . Furthermore, if the outer diameter of the rotor is polished after all assembly, the polished iron powder will adhere to the magnetized rotor surface and clog the motor gap, making it impossible to drive.

As another conventional method, as shown in FIG. 10, there is a multi-pole magnetizer 19 equipped with magnetized iron core teeth 18 around which a radial magnetizing coil 17 is wound. ) is quite short at 1 to 4 m, so it is technically impossible to wind the magnetizing coil 17 around the magnetized iron core teeth ] 8 within this pitch with a sufficient number of turns to obtain a sufficient magnetizing magnetic field.

Therefore, the present invention provides a highly efficient motor manufacturing method by collectively magnetizing the bar-shaped permanent magnets embedded in the tooth grooves of the rotor core and the disc-shaped permanent magnets for the main magnetic flux field between the rotor core. The purpose is to provide a magnetizer for stepping motors with high torque and high output.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a plurality of rotor teeth on the outer circumferential surface and two rotor teeth in the axial direction.
It has a divided block-shaped rotor core, and the rotor teeth slide against each other, and rod-shaped permanent magnets magnetized in the radial direction are fixed in the grooves of the rotor teeth, and the divided parts of the rotor core are magnetized in the axial direction. In a magnetizer for a stepping motor having a rotor in which a disc-shaped permanent magnet is sandwiched between the rod-shaped permanent magnets and the polarity of the bar-shaped permanent magnet is set in a direction to repel the field main magnetic flux generated from the disc-shaped permanent magnet lump, the disc-shaped permanent magnet is magnetized. It has a first coil that forms an axial magnetizing magnetic field to The magnetizing yoke to be provided is formed from a magnetic material, and the center part is magnetically divided into two parts by an annular non-magnetic material and mechanically connected to each other, and by incorporating the rotor, it connects to the outer peripheral surface of the rotor core of each block in a disc-shaped manner. The yoke faces the rotor core surface so that the axial surface that does not face the permanent magnet is the magnetic path cross section, forming an independently closed magnetic circuit, which is divided into each magnetized yoke and the rotor core of each block. The direction of rotation of the magnetic flux loops is the same,
The structure is such that the first coil is provided on the inner circumferential surface of a non-magnetic material.

(Function) The two magnetized yokes are magnetically insulated with a non-magnetic material, and the rotation direction of the magnetic flux loop formed by the two magnetized yokes and the rotor core of each block in the axial direction is the same, so each block The direction of the radial magnetizing magnetic flux passing through the rod-shaped permanent magnets in the grooves of the rotor teeth is opposite in the rotor core of each block.

Therefore, the magnetization directions of the rod-shaped permanent magnets in the grooves of the rotor core of each block are also magnetized with opposite polarities.

Further, the first coil, which is provided on the circumferential surface of the non-magnetic body and is used to magnetize the disc-shaped permanent magnet, has a magnetic path in an open state due to the non-magnetic material, and forms a magnetizing magnetic field that penetrates the rotor in the axial direction. By making the direction the same as the axial component formed within the rotor core by the two second coils that form a radial magnetizing magnetic field, the disk-shaped permanent magnets repel the magnetic flux produced by the bar-shaped permanent magnets. The magnet is axially magnetized in the direction.

Therefore, if you use this magnetizer, after processing and assembling the rotor with the permanent magnets unmagnetized, you can simultaneously attach the radially magnetized bar-shaped permanent magnets and the axially magnetized disk-shaped permanent magnets. Since it can be magnetized, it is easy to manufacture a motor.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view showing one embodiment of the present invention, and FIG.
The figure is a cross-sectional view taken along line A-A in FIG. 1.

1 and 2, the magnetizer 20 includes a coil 21 that forms an axial magnetizing magnetic field for magnetizing the disk-shaped permanent magnet 9, and rotor teeth 8a of each rotor core 7a, 7b.
, 8b, a rod-shaped permanent magnet 10a is embedded in the groove.

1. It is composed of two coils 22a and 22b that form a radial magnetizing magnetic field for magnetizing Ob, and a magnetizing yoke z3. Here, the magnetizing yoke 23 is made of a magnetic material, and is magnetically polarized by a non-magnetic ring 24 at the center.
It has divided yokes 23a and 23b, which are mechanically coupled. Furthermore, by incorporating the rotor 11 of the stepping motor into the magnetizer 20, the magnetizing yoke 23 magnetizes the circumferential core surface of the rotor core 7a of one block and the axial core surface that does not face the disk-shaped permanent magnets 9. The yoke 23a forms a closed magnetic circuit with respect to the rotor core surface so as to form a magnetic flux loop 25a, and similarly forms a closed magnetic circuit with the rotor core 7b of another block. , to create a magnetic flux loop 25b. moreover.

The yokes 23a and 23b of the magnetizing yoke 23 and the rotor core 7a.

The magnetic flux loops 25a and 25b formed by the magnetic flux loops 25a and 25b rotate in the same direction, and an axial magnetizing coil 21 for magnetizing the disk-shaped permanent magnet 9 is provided on the inner peripheral surface of the non-magnetic ring 24.

The yokes 23a and 23b described above are configured so that they can be divided in the axial direction in order to attach the coils 22a and 22b, respectively, and the yoke 23b has a A lid 26 is provided on the outer side.

Next, the operation of the embodiment configured as above will be explained.

Since the two yokes 23a and 23b are magnetically insulated by the non-magnetic ring 24, the magnetizing yoke 23 and the rotor core 7 form two magnetically independent magnetic circuits.
Two magnetic flux loops 25a and 25b shown in FIG. 1 are created. Since the magnetic flux loops 25a and 25b rotate in the same direction, the rod-shaped permanent magnets 10a are located in the grooves of the rotor teeth 8a and 8b of the two blocks, as shown in the figure.

The direction of the radial magnetizing flux passing through 10b is in the opposite direction,
The magnetization directions of the rod-shaped permanent magnets 10a and 10b in the respective grooves of the rotor teeth 8a and 8b of the two rotor cores 7a and 7b are also magnetized in an opposite relationship.

Next, the magnetizing coil 21 for magnetizing the disk-shaped permanent magnet 9 provided on the inner peripheral surface of the non-magnetic link 24 is an air-core coil fixed by the non-magnetic ring 24.

Therefore, the magnetic circuit is in an open state, and the rotor 11
A magnetizing magnetic field is created that passes through the axial direction. The direction of this magnetizing magnetic field is directed to the rotor core 7a by two coils 22a and 22b which form a radial magnetizing magnetic field as indicated in 1.

The direction is the same as the axial component formed within 7b.

As a result, the disk-shaped permanent magnet 9 becomes a bar-shaped permanent magnet], O
a.1. It is magnetized in the axial direction in a direction that repels the magnetic flux caused by Ob. FIG. 3 shows the rotor of a stepping motor being magnetized in a magnetizer 20. FIG.

Therefore, by using this magnetizer, after processing and assembling the rotor with the permanent magnets in an unmagnetized state, the radially magnetized bar-shaped permanent magnets 10a, 10b and the axially magnetized disc-shaped permanent magnet 9 are assembled. can be magnetized all at once, making motor production easier.

In addition, although the example described in 1 is a case where the disk-shaped permanent magnet 9 is provided on the rotor, it is naturally the same when the disk-shaped permanent magnet is provided on the stator, and the relationship between the rotor and the stator is reversed. However, if a stator magnetizer is manufactured in the same manner as the rotor magnetizer of the present invention, similar effects can be obtained. Further, since a stepping motor is an inductor type electric machine, the same effect can be obtained if the present invention is used as a magnetizer for other inductor type motors/generators (including linear motors).

11- [Effects of the Invention] As explained above, according to the present invention, it is possible to magnetize all the unmagnetized bar-shaped permanent magnets and disk-shaped permanent magnets attached to the rotor at once, and further, the rotor Manufacture is easy because the permanent magnet is magnetized after assembly and outer periphery polishing.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG. FIG. 4 is a vertical cross-sectional view of the high-torque stepping motor to which the present invention is applied, and FIG. 5 is a cross-sectional view taken along line A-A in FIG. 4. 6(a) and 6(b) are enlarged sectional views of FIG. 4, (a) is a sectional view taken along line X-X of FIG. 4, and (b) is a sectional view taken along line - A cross-sectional view taken along the Y line, Figure 7 is a vertical cross-sectional view of an air-core coil magnetizer used to magnetize the permanent magnets of a conventional stepping motor, and Figure 8 is a vertical cross-sectional view of a conventional stepping motor with a rod-shaped permanent magnet installed. +1 FIG. 9 is an explanatory diagram showing a state in which magnetized rod-shaped permanent magnets are inserted into the grooves along the axial direction of the rotor in the state shown in FIG. 8,
FIG. 10 is an enlarged view of a magnetizing coil portion of a conventional multi-pole magnetizer.

Claims (1)

[Claims] A rod-shaped permanent magnet having a block-shaped rotor core with a plurality of rotor teeth on the outer peripheral surface and divided into two in the axial direction, the rotor teeth being shifted from each other, and magnetized in the radial direction in the grooves of the rotor teeth. A rotor in which a disc-shaped permanent magnet magnetized in the axial direction is sandwiched between the divided portions of the rotor core, and the polarity of the bar-shaped permanent magnet is in a direction to repel the field main magnetic flux generated by the disc-shaped permanent magnet. A magnetizer for a stepping motor having a first coil that forms an axial magnetizing magnetic field that magnetizes the disc-shaped permanent magnet, and two coils that form a radial magnetizing magnetic field that magnetizes the rod-shaped permanent magnet. The magnetizing yoke provided with the two second coils is formed from a magnetic material, and the center portion is magnetically divided into two parts by an annular non-magnetic material and mechanically coupled to each other. In addition, by incorporating the rotor, the yoke is made to face the rotor core surface so that the outer circumferential surface of the rotor core of each block and the axial surface that does not oppose the disk-shaped permanent magnet form a magnetic path cross section, and are independent. to form a closed magnetic circuit,
The rotating direction of the magnetic flux loop formed by the divided magnetized yokes and the rotor core of each block is the same, and the first coil is provided on the inner circumferential surface of the non-magnetic material. Magnetizer for stepping motor.